It's a good thing that cities aspire to lead the way in acting on climate change in the absence of stronger national action. But a closer look reveals the limitations of current city-based efforts.

Climate crusaders: President Macron, right, with Paris Mayor Anne Hidalgo and former New York City mayor Michael Bloomberg after a June 2 meeting at the Elysee Palace, following the US withdrawal from the Paris agreement.
Christophe Petit Tesson/ReutersJune 27, 2017